1. Field of the Invention
This invention relates generally to turret moored offshore vessels and in particular to a radial elastomeric spring arrangement for the main bearing of a mooring turret to compensate for hull deflections or distortions of the moored vessel.
2. Description of the Prior Art
Heretofore, elastomeric springs have been provided for supporting an upper bearing of a mooring turret for a moored vessel. For example, U.S. Pat. No. 5,515,804 dated May 14, 1996 shows a bearing support for a mooring turret in which a plurality of equally spaced resilient support structures support the upper bearing. Each support structure includes a post secured to the turret and extending downwardly from the turret at a 45 degree angle with a plurality of elastomeric shear pads between upper and lower post portions of each post The heavy weight of the mooring chains causes bending of an upper hull beam and the shear pads in the posts may move closer together or further apart as a result of unequal forces from the mooring chains.
Other elastomeric arrangements for reacting radial loads or forces from a turret mounted on a main bearing have included a plurality of radially extending support members mounted about the turret and having elastomeric bumper pads between the turret and hull of the moored vessel. The elastomeric bumper pads act as shock absorbing devices to assist in limiting radial deflection of the turret.
3. Identification of Object of the Invention
A principal object of the invention is to provide a radial spring arrangement between main bearing of a mooring turret and a vessel which compensates for ovaling of the vessel due to environmental forces at sea on the vessel.